Tile on wooden floors bouncy

[Painters10]

I've just started tiling a new floor in an extension. The floor is treated chipboard (Caberdek) and is well secured down and nice and flat.

As an adhesive I got Unibond "Tile on Floors" Waterproof Adhesive. It's a powder and its not a rapid set type.

I laid the first tiles last night and out of curiosity I tested whether they are stuck. But they feel "bouncy". If you get down to floor level you can actually see the tiles move up and down (at the edges anyway) as you move on them.

Is that normal for an adhesive meant for tiling directly onto wood? I've only ever put tiles onto concrete floors before.

Cheers Painters10

[Tim Watts]

On Fri, 16 Apr 2010 12:40:52 -0700, Painters10 wibbled:

1) Check the adhesive says it is a "Class S2" - that's the most flexible I've come across; Make sure the grout is a flexible type too (easily overlooked). 2) I think you have too much bounce. I can't be sure, as I've not tiled onto wood, but only onto marmox foam panels which also have some "give" and need a flexible adhesive and grout. Anyway, it would worry me and if it were me, I would overboard with ply to increase stiffness, or replace the chip with thick[1] ply. [1] Depending on joist spacing...

HTH

Tim

[NT]

sounds like you dont have a hope in hell of that working

NT

[Tim Watts]

On Fri, 16 Apr 2010 14:38:34 -0700, NT wibbled:

I agree. Having thought some more, if you can see the bounce, you're stuffed.

Flexi tile adhesive is for the bounce you can't see (but is still there).

[spamlet]

We had our kitchen done with tiles over wood a few years back. The floor was raised for the sink pipes to go under. The tiles did not stay stuck for long, and many of them broke. Another time we would insist on decent thick tongue and groove board rather than just floor boards, and the best flexible cement and grout (though this does seem scarily expensive!). (Shame we didn't have enough t&g oak left over from the living room cos that is still nice and stiff, and warm on the feet.) Mind you, as the kitchen tiles are cold on the feet anyway, why didn't we just use more of the oak on its own in the first place?

As we still need to have this redone can anyone recommend the adhesive and grout that are the most likely to flex and not crumble? Yes, I know: oak boards would be much nicer, but its not me you have to convince...

S

[spamlet]

Having said all that, I'd quite like to try the effect of laying a rubber sheet and sticking the tiles to that with solvent adhesive and then 'grouting' with rtv... Could make a nice shock absorbent floor more kind to dropped plates...

S

[Tim Watts]

spamlet wibbled on Saturday 17 April 2010 02:16

Hope you busted the bloke's ****s who did it :(

BTW - you really want ply for this, not T+G.

Not necessarily. Mapei (as well as most other major manufacturer) do both flexible powder adhesives and an additive liquid that gives Class S2 properties to some of their other powdered adhesives. Although not cheap like some basic B&Q ownbadged stuff, compared to the cost of the tiles (and labour if someone else is doing it), I didn't think the funky adhesives were particulary expensive.

[NT]

Then the tiles all crack. They're just not tolerant of non-solid support, ceramic tiles rely heavily on what's under them for strength.

NT

[The Medway Handyman]

IMO ceramic tiling onto any wooden floor is just asking for trouble regardless of prep, adhesive & grout. It's agin nature, no good will come of it.

[Tim Watts]

The Medway Handyman wibbled on Saturday 17 April 2010 16:31

I do know of two people who have hard tiles on suspended floors, done properly, and it can work very well (not a crack in sight) - but it's in the preparation and use of correct materials :)

[The Natural Philosopher]

The key is to get rid of the bounce before you tile. Tiles cant cope with much flexing even with a flexy adhesive.

If that means relaying te floor with deeper joists and herring boning them, so be it.

Otherwise stick to vinyl.

[spamlet]

Cheers for the tip Tim.

Having looked through the general gist of the thread, I think I'm going to try and convince others that a nice warm oak floor would be much better!

(I wasn't keen on ply in case we needed to get at the pipes at some point - and was thus a bit iffy about tiles in the first place...)

S

[Tim Watts]

spamlet wibbled on Saturday 17 April 2010 20:43

The specific adhesive combo I've used is Mapei Kerabond (12+VAT bag) mixed with Isolastic in place of the water (20+VAt for 5l, can be got in 1l bottles).

've not bought anything from them, but my usual supplier for Mapei has just let a raving pillock loose on their website (yes, you Ray!) and everything is broken in more than one way - so I can't give any links to them (though I did email both them and Ray give them the "unhappy customer" speel.

Pipes under there. Ooh. Yes, I agree - no way I'd tile that unless I could move any pipes and cables such that they could be got at from an adjacent room or were in boxing above floor.

Anyway - yes - oak (actual or engineered) is quite civilised on the tootsies (I have engineered in the bedrooms). Through, shoving 20mm Marmox under ceramic tiles on uninsulated concrete in the ground floor bathroom actually leaves that floor quite comfortable too - even with no UFH.

[Jules Richardson]

They have recommended minimum deflection measurements over here for subfloors which dictate whether they're suitable for various types of tile... it seems it can certainly work if done right.

Been there, done that in the last couple of weeks... my first ever tiling project (I built the joists/subfloor beneath, too). I'm currently paranoid about cracking tiles :-)

cheers

Jules

[Jules Richardson]

That's my understanding, too. Make the subfloor as strong as you can possibly get it. Opinion seems divided on chip vs. ply, but the thicker the better. Make sure your joist spacing/spans beneath are good, use a layer of cement backer board beneath the tiles etc.

cheers

Jules

[The Natural Philosopher]

Tight as a drum or as a ducks arse, is what you want to aim for Jules..

dont finish the job: wait a week and jump on the worst place. If the tiles crack off, think again.

What is acceptable deflection for humans, may not be for tiles.

[Jules Richardson]

Yeah, it basically ends up like that. If you can feel it move when you jump on it, it's definitely no good...

I pretty much did that, as I set all my whole tiles the middle of last week, but didn't get around to cutting all the partial ones at the edges and around doors until today. I've not actively bounced up and down on it yet, but I've been thumping around back there and so far so good...

I had major height restrictions for the subfloor in there, so I ran my joists every 12" (rather than the typical 16" here) and then supported them every 2'. My main worry is whether there's too much bounce between joists though - that and whether I'm any good at laying mortar ;-)

cheers

Jules

[Painters10]

Thanks for the pointers. An update to the original post... The tile adhesive had failed to stick to the tiles but had stuck to the floor. I decided to get the unibond stuff off, so after much scraping I got back to wood. I then sealed with BAL SBR and stuck the tiles down with Ardex 7001 (wow that stuff is expensive). Finally grouted with BAL flexible grout.

The Ardex went down nicely and all looks great. Time will tell if it stays that way.

Painters10

[spamlet]

With our version, the adhesive stuck to the tiles but not the wood. Looks like you were luckier than us: hope it stays that way. Keep us posted.

Cheers, S